The goal of this research program is to extend the usefullness of electroencephalographic evoked potentials as a noninvasive means of estimating cortical response of the brain and thereby to increase its value as a measurement and analysis tool in research on human development and function. This will be accomplished through development of special signal measuring and processing technique capable of providing quantitative estimates of parameters associated with individual responses and components of individual responses as opposed to the averaging techniques widely employed at the present time. An important part of this research will be the establishment of quanitative descriptions of evoked responses that take into account shifts in latency and amplitude of the separate components of the individual responses. By carefully accounting for these shifts in latency and amplitude variation of individual responses it is hoped to reduce the wide margins of normalcy that have been found in developmental studies in the past and to permit valuable comparisons to be made of responses from widely varying stimuli. Development and testing of the processing techniques will be carried out utilizing simulated responses based on published data of a number of researchers. The simulated responses will provide for variable noise characteristics and for variations in latency and amplitude of the total response and among the components of individual responses. The optimum processing techniques that are developed will be applied to human responses to visual, auditory and somatosensory stimuli initially and later to responses to patterned stimuli and to developmental data obtained by other researchers.